Absorbent article with tackifier-free adhesive

ABSTRACT

Disposable absorbent articles assembled from a collection of components using an adhesive comprising an amorphous polyolefin composition and a heterophase polyolefin composition comprising amorphous character and crystalline blocks.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. § 120 to and is acontinuation of U.S. patent application Ser. No. 15/915,146, filed onMar. 8, 2018, which is a continuation of U.S. patent application Ser.No. 15/382,779, filed on Dec. 19, 2016, now U.S. Pat. No. 9,943,623,which is a continuation of U.S. patent application Ser. No. 14/968,932,filed Dec. 15, 2015, now U.S. Pat. No. 9,555,152, which is acontinuation of U.S. patent application Ser. No. 14/302,725, filed Jun.12, 2014, now U.S. Pat. No. 9,241,843, which is a continuation-in-partof U.S. patent application Ser. No. 13/836,385, filed Mar. 15, 2013, nowU.S. Pat. No. 8,865,824, which claims the benefit of U.S. ProvisionalApplication No. 61/702,950, filed on Sep. 19, 2012, all of which arehereby incorporated by reference in their entirety.

FIELD

This invention relates to the adhesive material, typically a hot meltadhesive, that is used to assemble components into an absorbent articlesuch as a diaper (i.e. the construction adhesive). In particular, thisinvention relates to such absorbent articles assembled using aconstruction adhesive that is substantially free of a tackifier.

BACKGROUND

Users, for example caregivers, rely on disposable absorbent articles tomake their lives easier. Disposable absorbent articles, such as adultincontinence articles, diapers, and training pants are generallymanufactured by combining several components. These components typicallyinclude a liquid-permeable topsheet, a liquid-impermeable backsheetattached to the topsheet, and an absorbent core located between thetopsheet and the backsheet. When the disposable article is worn, theliquid-permeable topsheet is positioned next to the body of the wearer.The topsheet allows passage of bodily fluids into the absorbent core.The liquid-impermeable backsheet helps prevent leakage of fluids held inthe absorbent core. The absorbent core generally is designed to havedesirable physical properties, e.g. a high absorbent capacity and highabsorption rate, so that bodily fluids can be transported from the skinof the wearer into the disposable absorbent article.

Frequently one or more components of a disposable absorbent article areadhesively bonded together. For example, adhesives have been used tobond individual layers of the absorbent article, such as the topsheetand backsheet together. Adhesives have also been used to bond discretecomponents, such as fasteners and leg elastics or cuffs, to the article.The adhesive is often called a construction adhesive because it is usedto help construct the absorbent article from individual components.

In many instances, a hot-melt adhesive is used as a constructionadhesive. Common hot-melt adhesives are made by combining polymer andadditive components in a substantially uniform thermoplastic blend.Typical additives may include tackifiers, plasticizers, and/or waxes,for example. While such formulations generally work, they can be costlyand their performance properties can be improved. For example,tackifiers, which can comprise up to 65% of an adhesive formula, can beexpensive and difficult to source. Therefore, there is a continuing needfor improved construction adhesives that offer better performance andlower cost.

SUMMARY

The present invention relates to disposable absorbent articles assembledfrom a collection of components using an adhesive comprising anamorphous polyolefin composition and a heterophase polyolefincomposition comprising amorphous character and crystalline blocks.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of an exemplary absorbent article in a flat,uncontracted state.

DETAILED DESCRIPTION

As used herein, the following terms shall have the meaning specifiedthereafter:

“Disposable,” in reference to absorbent articles, means that theabsorbent articles are generally not intended to be laundered orotherwise restored or reused as absorbent articles (i.e., they areintended to be discarded after a single use and, preferably, to berecycled, composted or otherwise discarded in an environmentallycompatible manner).

“Absorbent article” refers to devices which absorb and contain bodyexudates and, more specifically, refers to devices which are placedagainst or in proximity to the body of the wearer to absorb and containthe various exudates discharged from the body. Exemplary absorbentarticles include diapers, training pants, pull-on pant-type diapers(i.e., a diaper having a pre-formed waist opening and leg openings suchas illustrated in U.S. Pat. No. 6,120,487), refastenable diapers orpant-type diapers, adult incontinence briefs and undergarments, diaperholders and liners, feminine hygiene garments such as panty liners,absorbent inserts, and the like.

“Proximal” and “Distal” refer respectively to the location of an elementrelatively near to or far from the longitudinal or lateral centerline ofa structure (e.g., the proximal edge of a longitudinally extendingelement is located nearer to the longitudinal centerline than the distaledge of the same element is located relative to the same longitudinalcenterline).

“Body-facing” and “garment-facing” refer respectively to the relativelocation of an element or a surface of an element or group of elements.“Body-facing” implies the element or surface is nearer to the wearerduring wear than some other element or surface. “Garment-facing” impliesthe element or surface is more remote from the wearer during wear thansome other element or surface (i.e., element or surface is proximate tothe wearer's garments that may be worn over the disposable absorbentarticle).

“Longitudinal” refers to a direction running substantially perpendicularfrom a waist edge to an opposing waist edge of the article and generallyparallel to the maximum linear dimension of the article. Directionswithin 45 degrees of the longitudinal direction are considered to be“longitudinal”.

“Lateral” refers to a direction running from a longitudinal edge to anopposing longitudinal edge of the article and generally at a right angleto the longitudinal direction. Directions within 45 degrees of thelateral direction are considered to be “lateral.”

“Disposed” refers to an element being located in a particular place orposition.

“Joined” refers to configurations whereby an element is directly securedto another element by affixing the element directly to the other elementand to configurations whereby an element is indirectly secured toanother element by affixing the element to intermediate member(s) whichin turn are affixed to the other element.

“Film” refers to a sheet-like material wherein the length and width ofthe material far exceed the thickness of the material. Typically, filmshave a thickness of about 0.5 mm or less.

“Water-permeable” and “water-impermeable” refer to the penetrability ofmaterials in the context of the intended usage of disposable absorbentarticles. Specifically, the term “water-permeable” refers to a layer ora layered structure having pores, openings, and/or interconnected voidspaces that permit liquid water, urine, or synthetic urine to passthrough its thickness in the absence of a forcing pressure. Conversely,the term “water-impermeable” refers to a layer or a layered structurethrough the thickness of which liquid water, urine, or synthetic urinecannot pass in the absence of a forcing pressure (aside from naturalforces such as gravity). A layer or a layered structure that iswater-impermeable according to this definition may be permeable to watervapor, i.e., may be “vapor-permeable.”

“Extendibility” and “extensible” mean that the width or length of thecomponent in a relaxed state can be extended or increased.

“Elastic,” “elastomer,” and “elastomeric” refer to a material whichgenerally is able to extend to a strain of at least 50% without breakingor rupturing, and is able to recover substantially to its originaldimensions after the deforming force has been removed.

“Elastomeric material” is a material exhibiting elastic properties.Elastomeric materials may include elastomeric films, scrims, nonwovens,and other sheet-like structures.

“Outboard” and “inboard” refer respectively to the location of anelement disposed relatively far from or near to the longitudinalcenterline of the diaper with respect to a second element. For example,if element A is outboard of element B, then element A is farther fromthe longitudinal centerline than is element B.

“Pant” refers to disposable absorbent articles having a pre-formed waistand leg openings. A pant may be donned by inserting a wearer's legs intothe leg openings and sliding the pant into position about the wearer'slower torso. Pants are also commonly referred to as “closed diapers”,“prefastened diapers”, “pull-on diapers”, “training pants” and“diaper-pants.”

“Nonwoven” fabric or web means a web having a structure of individualfibers or threads that are interlaid, but not in a regular oridentifiable manner as in a knitted fabric. Nonwoven fabrics or webshave been formed from many processes such as, for example, meltblowingprocesses, spunbonding processes, air laying processes, and bondedcarded web processes. The basis weight of nonwoven fabrics is usuallyexpressed in ounces of material per square yard (osy) or grams persquare meter (gsm) and the fiber diameters are usually expressed inmicrons. (Note: to convert from osy to gsm, multiply osy by 33.91.)

“Substrate” is used herein to describe a material that is primarilytwo-dimensional (i.e., in an XY plane) and whose thickness (in a Zdirection) is relatively small (i.e. 1/10 or less) in comparison to itslength (in an X direction) and width (in a Y direction). Non-limitingexamples of substrates include a web, layer or layers of fibrousmaterials, nonwovens, and films and foils, such as polymeric films ormetallic foils, for example. These materials may be used alone or maycomprise two or more layers laminated together. As such, a web may be asubstrate or may be a laminate of two or more substrates.

“Spunbonded fibers”, or “spunbond fibers”, means small-diameter fibersthat are typically formed by extruding molten thermoplastic material asfilaments from a plurality of fine capillaries of a spinneret having acircular or other configuration, with the diameter of the extrudedfilaments then being rapidly reduced as by, for example, in U.S. Pat.Nos. 4,340,563, 3,692,618, 3,802,817, 3,338,992, 3,341,394, 3,502,763,3,502,538, and 3,542,615. Spunbond fibers are quenched and generally nottacky when they are deposited onto a collecting surface. Spunbond fibersare generally continuous and often have average diameters larger thanabout 7 microns, and more particularly between about 10 and 30 microns.A spunbond material, layer, or substrate comprises spunbonded (orspunbond) fibers.

“Meltblown fibers” means fibers formed by extruding a molten material,typically thermoplastic in nature, through a plurality of fine, usuallycircular, die capillaries as molten threads or filaments into converginghigh-velocity heated gas (e.g., air) streams that attenuate thefilaments of molten material to reduce their diameter, which may be tomicrofiber diameter. Thereafter, the meltblown fibers are carried by thehigh-velocity gas stream and are deposited on a collecting surface toform a web of randomly dispersed meltblown fibers. Such a process isdisclosed for example, in U.S. Pat. No. 3,849,241. Meltblown fibers aremicrofibers which may be continuous or discontinuous, are generallysmaller than 10 microns in diameter, and are generally self-bonding whendeposited onto a collecting surface

“Microfibers” means small-diameter fibers having an average diameter notgreater than about 100 microns, for example, having a diameter of fromabout 0.5 microns to about 50 microns, more specifically microfibers mayalso have an average diameter of from about 1 micron to about 20microns. Microfibers having an average diameter of about 3 microns orless are commonly referred to as ultra-fine microfibers. A descriptionof an exemplary process of making ultra-fine microfibers may be foundin, for example, U.S. Pat. No. 5,213,881.

“Homopolymer” means a polymer resulting from the polymerization of asingle monomer, i.e., a polymer consisting essentially of a single typeof repeating unit.

“Copolymer(s)” refers to polymer(s) formed by the polymerization of atleast two different monomers. For example, the term “copolymer” includesthe copolymerization reaction product of a monomer such as propene or2-butene, preferably 1-butene and an α-olefin, such as for example,ethylene, 1-hexene or 1-octene.

“Propene copolymer” or “propylene copolymer” means a copolymer ofgreater than 40 or 50 wt. % or more propene and at least one monomerselected from the group including ethylene and a C₄ to C₂₀ α-olefin.

“Butene copolymer” means a polymer of n-butene (1-butene) or 2-buteneand at least one monomer selected from the group of C₂₋₃ and C₅₋₂₀ alphaolefins. Butene copolymers typically comprise a minimum amount at leastabout 40 or about 50 wt. % or more of a butene monomer such as 1-butene.

“Heterophase” polymer means a polymer having an amorphous character andat least some substantial crystalline content (at least 5 wt. %, 10 wt.%, 20 wt. %, 40 wt. % or 50 wt. % crystalline content) that can providecohesive strength in the cooled adhesive mass. The crystalline contentcan be in the form of stereoregular blocks or sequences.

“Amorphous” means the substantial absence of crystallinity, (i.e.) lessthan 5% and less than 1%.

“Sequence or block” means a polymer portion of repeating monomer that issimilar in composition, crystallinity or other aspect.

“Open time” means the amount of time elapsed between application of amolten hot melt adhesive composition to a first substrate, and the timewhen useful tackiness or wetting out of the adhesive on a substrateeffectively ceases due to solidification of the adhesive composition.Open time is also referred to as “working time.”

“Substantially” means generally the same or uniform but allowing for orhaving minor fluctuations from a defined property, definition, etc. Forexample, small measurable or immeasurable fluctuations in a measuredproperty described herein, such as viscosity, melting point, etc. mayresult from human error or methodology precision. Other fluctuations arecaused by inherent variations in the manufacturing process, thermalhistory of a formulation, and the like. The adhesive compositions ofthe, nonetheless, would be said to be substantially having the propertyas reported.

“Major proportion” means that a material or monomer is used at greaterthan 50 wt. %.

“Primary component” means that a material or monomer is the more commonsubstance or has the higher concentration in the mixture or polymercompared to others but may not be as much as 50 wt. %.

“Hot-melt processable” means that an adhesive composition may beliquefied using a hot-melt tank (i.e., a system in which the compositionis heated so that it is substantially in liquid form) and transportedvia a pump (e.g., a gear pump or positive-displacement pump) from thetank to the point of application proximate a substrate or othermaterial; or to another tank, system, or unit operation (e.g., aseparate system, which may include an additional pump or pumps, fordelivering the adhesive to the point of application). Hot-melt tanksused to substantially liquefy a hot-melt adhesive typically operate in arange from about 38° C. to about 230° C. Generally, at the point ofapplication, the substantially liquefied adhesive composition will passthrough a nozzle or bank of nozzles, but may pass through some othermechanical element such as a slot. A hot-melt processable adhesivecomposition is to be contrasted with a composition that requires aconventional extruder, and the attendant pressures and temperaturescharacteristic of an extruder, to liquefy, mix, and/or convey thecomposition. While a hot-melt tank and pump in a hot-melt processingsystem can handle adhesive-composition viscosities in a range from about1000 centipoise to about 10,000 centipoise, an extruder can handle andprocess adhesive-composition viscosities in a range from about 10,000centipoise to viscosities of several hundred thousand centipoise.

Unless otherwise noted, “Laminated structure” or “laminate” means astructure in which one layer, material, component, web, or substrate isadhesively bonded, at least in part, to another layer, material,component, web, or substrate. As stated elsewhere in this application, alayer, material, component, web, or substrate may be folded over andadhesively bonded to itself to form a “laminated structure” or“laminate.”

FIG. 1 is a plan view of an exemplary, non-limiting embodiment of adiaper 20 of the present invention in a flat, uncontracted state (i.e.,without elastic induced contraction). The garment-facing surface 120 ofthe diaper 20 is facing the viewer. The diaper 20 includes alongitudinal centerline 100 and a lateral centerline 110. The diaper 20may comprise a chassis 22. The diaper 20 and chassis 22 are shown tohave a front waist region 36, a rear waist region 38 opposed to thefront waist region 36, and a crotch region 37 located between the frontwaist region 36 and the rear waist region 38. The waist regions 36 and38 generally comprise those portions of the diaper 20 which, when worn,encircle the waist of the wearer. The waist regions 36 and 38 mayinclude elastic elements such that they gather about the waist of thewearer to provide improved fit and containment. The crotch region 37 isthat portion of the diaper 20 which, when the diaper 20 is worn, isgenerally positioned between the legs of the wearer.

The outer periphery of chassis 22 is defined by longitudinal side edges12 and end edges 14. The chassis 22 may have opposing longitudinal sideedges 12 that are oriented generally parallel to the longitudinalcenterline 100. However, for better fit, longitudinal side edges 12 maybe curved or angled to produce, for example, an “hourglass” shape diaperwhen viewed in a plan view. The chassis 22 may have opposing lend edges14 that are oriented generally parallel to the lateral centerline 110.

The chassis 22 may comprises a liquid permeable topsheet 24 havinglongitudinal side edges 25, a backsheet 26, and an absorbent core 28between the topsheet 24 and the backsheet 26. The absorbent core 28 mayhave a body-facing surface and a garment facing-surface. The topsheet 24may be joined to the core 28 and/or the backsheet 26. The backsheet 26may be joined to the core 28 and/or the topsheet 24. It should berecognized that other structures, elements, or substrates may bepositioned between the core 28 and the topsheet 24 and/or backsheet 26.In certain embodiments, the chassis 22 comprises the main structure ofthe diaper 20 with other features may added to form the composite diaperstructure. While the topsheet 24, the backsheet 26, and the absorbentcore 28 may be assembled in a variety of well-known configurations,preferred diaper configurations are described generally in U.S. Pat.Nos. 3,860,003; 5,151,092; 5,221,274; 5,554,145; 5,569,234; 5,580,411;and 6,004,306.

The topsheet 24 is generally a portion of the diaper 20 that may bepositioned at least in partial contact or close proximity to a wearer.Suitable topsheets 24 may be manufactured from a wide range ofmaterials, such as porous foams; reticulated foams; apertured plasticfilms; or woven or nonwoven webs of natural fibers (e.g., wood or cottonfibers), synthetic fibers (e.g., polyester or polypropylene fibers), ora combination of natural and synthetic fibers. The topsheet 24 isgenerally supple, soft feeling, and non-irritating to a wearer's skin.Generally, at least a portion of the topsheet 24 is liquid pervious,permitting liquid to readily penetrate through the thickness of thetopsheet 24. A particularly preferred topsheet 24 is available from BBAFiberweb, Brentwood, Tenn. as supplier code 055SLPV09U.

Any portion of the topsheet 24 may be coated with a lotion as is knownin the art. Examples of suitable lotions include those described in U.S.Pat. Nos. 5,607,760; 5,609,587; 5,635,191; and 5,643,588. The topsheet24 may be fully or partially elasticized or may be foreshortened so asto provide a void space between the topsheet 24 and the core 28.Exemplary structures including elasticized or foreshortened topsheetsare described in more detail in U.S. Pat. Nos. 4,892,536; 4,990,147;5,037,416; and 5,269,775.

The absorbent core 28 may comprise a wide variety of liquid-absorbentmaterials commonly used in disposable diapers and other absorbentarticles. Examples of suitable absorbent materials include comminutedwood pulp, which is generally referred to as air felt creped cellulosewadding;

melt blown polymers, including co-form; chemically stiffened, modifiedor cross-linked cellulosic fibers; tissue, including tissue wraps andtissue laminates; absorbent foams; absorbent sponges; superabsorbentpolymers; absorbent gelling materials; or any other known absorbentmaterial or combinations of materials. These materials may be combinedto provide a core 28 in the form of one or more layers (individuallayers not shown) that may include fluid handling layers such asacquisition layers, distribution layers and storage layers. Theabsorbent core 28 may comprise a substrate layer, absorbent polymermaterial, and a fibrous layer of adhesive (not shown). Such absorbentcores 28 may also include layers (not shown) to stabilize other corecomponents. Such layers include a core cover and a dusting layer. Asuitable material for such layers is a spunbonded/meltblown/spunbondednonwoven having a basis weight between about 10 and 15 g/m² (themeltblown layer comprises <5 g/m²) as is available from Avgol America,Inc. of Knoxville, N.C. For example, Exemplary absorbent structures foruse as the absorbent core 28 are described in U.S. Pat. Nos. 4,610,678;4,673,402; 4,834,735; 4,888,231; 5,137,537; 5,147,345; 5,342,338;5,260,345; 5,387,207; 5,397,316; 5,625,222. To reduce the overall sizeand/or thickness of the absorbent core, and thereby improve wearercomfort and reduce the volume of disposable waste created by a soiledinsert, it may be desired to construct an absorbent core using thelowest volumes of core materials possible within performanceconstraints. Toward this end, examples of suitable materials andconstructions for a suitable absorbent core are described in, but arenot limited to, U.S. application Ser. Nos. 12/141,122 and 12/141,124;and U.S. Pat. Nos. 8,017,827; and 8,496,637. These generally describeabsorbent core constructions that minimize or eliminate the need for andinclusion of airfelt or other forms of cellulose fiber in combinationwith particles of superabsorbent polymer (hereinafter, “substantiallyairfelt-free cores”). The adhesives of the present invention may be usedwithin or near the core to immobilize the core, immobilize absorbentmaterial, or to bond the core substrate to the absorbent polymermaterial, among other uses. The construction of the absorbent core andadhesives used within the core may be such as described in U.S. Pat.Nos. 8,319,005 and 8,187,240, and in U.S. Publication No. 2012/0316530.In some embodiments, the adhesive may be fibrous or be a net-likestructure.

The backsheet 26 is generally positioned such that it may be at least aportion of the garment-facing surface 120 of the diaper 20. Backsheet 26may be designed to prevent the exudates absorbed by and contained withinthe diaper 20 from soiling articles that may contact the diaper 20, suchas bed sheets and undergarments. In certain embodiments, the backsheet26 is substantially water-impermeable. Suitable backsheet 26 materialsinclude films such as those manufactured by Tredegar Industries Inc. ofTerre Haute, Ind. and sold under the trade names X15306, X10962, andX10964. Other suitable backsheet 26 materials may include breathablematerials that permit vapors to escape from the diaper 20 while stillpreventing exudates from passing through the backsheet 26. Exemplarybreathable materials may include materials such as woven webs, nonwovenwebs, composite materials such as film-coated nonwoven webs, andmicroporous films such as manufactured by Mitsui Toatsu Co., of Japanunder the designation ESPOIR NO and by EXXON Chemical Co., of Bay City,Tex., under the designation EXXAIRE. Suitable breathable compositematerials comprising polymer blends are available from ClopayCorporation, Cincinnati, Ohio under the name HYTREL blend P18-3097. Suchbreathable composite materials are described in greater detail in PCTApplication No. WO 95/16746 and U.S. Pat. No. 5,865,823. Otherbreathable backsheets including nonwoven webs and apertured formed filmsare described in U.S. Pat. No. 5,571,096. An exemplary, suitablebacksheet is disclosed in U.S. Pat. No. 6,107,537. Other suitablematerials and/or manufacturing techniques may be used to provide asuitable backsheet 26 including, but not limited to, surface treatments,particular film selections and processing, particular filamentselections and processing, etc.

Backsheet 26 may also consist of more than one layer, as illustrated inthe cut-away of FIG. 1. The backsheet 26 may comprise an outer cover 26a and an inner layer 26 b. The outer cover 26 a may have longitudinalside edges 27 a and the inner layer 26 b may have longitudinal sideedges 27 b. The outer cover 26 a may be made of a soft, non-wovenmaterial. The inner layer 26 b may be made of a substantiallywater-impermeable film. The outer cover 26 a and an inner layer 26 b maybe joined together by adhesive or any other suitable material or method.A particularly suitable outer cover 26 a is available from Corovin GmbH,Peine, Germany as supplier code A18AH0, and a particularly suitableinner layer 26 b is available from RKW Gronau GmbH, Gronau, Germany assupplier code PGBR4WPR. While a variety of backsheet configurations arecontemplated herein, it would be obvious to those skilled in the artthat various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention.

The diaper 20 may also include a fastening system 50. When fastened, thefastening system 50 interconnects the front waist region 36 and the rearwaist region 38 resulting in a waist circumference that may encircle thewearer during wear of the diaper 20. The fastening system 50 maycomprises a fastener such as tape tabs, hook and loop fasteningcomponents, interlocking fasteners such as tabs & slots, buckles,buttons, snaps, and/or hermaphroditic fastening components, although anyother known fastening means are generally acceptable. Some exemplarysurface fastening systems are disclosed in U.S. Pat. Nos. 3,848,594;4,662,875; 4,846,815; 4,894,060; 4,946,527; 5,151,092; and 5,221,274. Anexemplary interlocking fastening system is disclosed in U.S. Pat. No.6,432,098. The fastening system 50 may also provide a means for holdingthe article in a disposal configuration as disclosed in U.S. Pat. No.4,963,140. The fastening system 50 may also include primary andsecondary fastening systems, as disclosed in U.S. Pat. No. 4,699,622.The fastening system 50 may be constructed to reduce shifting ofoverlapped portions or to improve fit as disclosed in U.S. Pat. Nos.5,242,436; 5,499,978; 5,507,736; and 5,591,152.

FIG. 1 depicts a fastening system 50 having an engaging member 52 and areceiving member 54. The engaging member 52 is shown having an engagingsurface 53 that may comprise hooks, loops, an adhesive, a cohesive, orother fastening member. The receiving member 54 may have a surface thatallows for engagement of the engaging member 52. The receiving member 54may comprise hooks, loops, an adhesive, a cohesive, or other fasteningcomponent that can receive the engaging member 52. Suitable engagingmember 52 and receiving member 54 combinations include but are notlimited to hooks/loop, hooks/hooks, adhesive/polymeric film;cohesive/cohesive, adhesive/adhesive; tab/slot; and button/button hole.

The diaper 20 may include barrier cuffs 60 and/or gasketing cuffs 70.Gasketing cuffs 70 may also be referred to as outer leg cuffs, legbands, side flaps, leg cuffs, or elastic cuffs. Barrier cuffs 60 mayalso be referred to as second cuffs, inner leg cuffs or “stand-up”elasticized flaps.

The gasketing cuff 70 may be substantially inelastic or may beelastically extensible to dynamically fit at the wearer's leg. Thegasketing cuff 70 may be formed by one or more elastic members 72 (suchas elastic strands) operatively joined to the topsheet 24, backsheet 26,or any other suitable substrate used in the formation of the diaper 20.Suitable gasketing cuff construction is further described in U.S. Pat.No. 3,860,003

The barrier cuff 60 may have a distal edge 61 and a proximal edge 63that run substantially parallel to the longitudinal centerline 100. Thebarrier cuff 60 may span the entire longitudinal length of the diaper20. The barrier cuff 60 may be formed by a flap 62 and an elastic member64 (such as elastic strands). The flap 62 may be a continuous extensionof any of the existing materials or elements that form the diaper 20. Inother embodiments, such as shown in FIG. 1, the barrier cuff 60 may be adiscrete element. In such embodiments, the barrier cuff 60 comprisingthe flap 62 and the elastic member 64 may be formed then joined to thechassis 22 by a bond 65.

The flap 62 may comprise a variety of substrates such as plastic filmsand woven or nonwoven webs of natural fibers (e.g., wood or cottonfibers), synthetic fibers (e.g., polyester or polypropylene fibers), ora combination of natural and synthetic fibers. In certain embodiments,the flap 62 may comprise a nonwoven web such as spunbond webs, meltblownwebs, carded webs, and combinations thereof (e.g., spunbond-meltblowncomposites and variants). Laminates of the aforementioned substrates mayalso be used to form the flap 62. A particularly suitable flap maycomprise a nonwoven available from BBA Fiberweb, Brentwood, Tenn. assupplier code 30926. A particularly suitable elastic member is availablefrom Invista, Wichita, Kans. as supplier code T262P. Further descriptionof diapers having barrier cuffs and suitable construction of suchbarrier cuffs may be found in U.S. Pat. Nos. 4,808,178 and 4,909,803.The elastic member 64 generally spans the longitudinal length of thebarrier cuff 60. In other embodiments, the elastic member 64 may span atleast the longitudinal length of the barrier cuff 60 within the crotchregion 37. It is desirable that the elastic member 64 exhibitssufficient elasticity such that the proximal edge 63 of the barrier cuff60 remains in contact with the wearer during normal wear, therebyenhancing the barrier properties of the barrier cuff 60. The elasticmember 64 may be connected to the flap 62 at opposing longitudinal ends.In certain embodiments, the flap 62 may be folded over onto itself so asto encircle the elastic member 64. A bond 67 may be used to secure thefolded section of the flap 62.

The barrier cuffs 60 and/or gasketing cuffs 70 may be treated, in fullor in part, with a lotion, as described above with regard to topsheets,or may be fully or partially coated with a hydrophobic surface coatingas detailed in U.S. application Ser. No. 11/055,743, which was filedFeb. 10, 2005. The diaper 20 may include front ears 40 and back ears 42.The front and/or back ears 40, 42 may be unitary elements of the diaper20 (i.e., they are not separately manipulative elements secured to thediaper 20, but rather are formed from and are extensions of one or moreof the various layers of the diaper). In certain embodiments, the frontand/or back ears 40, 42 may be discrete elements that are joined to thechassis 22, as shown in FIG. 1. Discrete front and/or back ears 40, 42may be joined to the chassis 22 by any bonding method known in the artsuch as adhesive bonding, pressure bonding, heat bonding, and the like.In other embodiments, the front and/or back ears 40, 42 may comprise adiscrete element joined to the chassis 22 with the chassis 22 having alayer, element, or substrate that extends over the front and/or back ear40, 42. The front ears 40 and back ears 42 may be extensible,inextensible, elastic, or inelastic. The front ears 40 and back ears 42may be formed from nonwoven webs, woven webs, knitted fabrics, polymericand elastomeric films, apertured films, sponges, foams, scrims, andcombinations and laminates thereof. In certain embodiments the frontears 40 and back ears 42 may be formed of a nonwoven/elastomericmaterial laminate or a nonwoven/elastomeric material/nonwoven laminate.A suitable elastic back ear 42 may be a laminate comprising anelastomeric film (such as is available from Tredegar Corp, Richmond,Va., as supplier code X25007) disposed between two nonwoven layers (suchas is available from BBA Fiberweb, Brentwood, Tenn. as supplier codeFPN332). While the following embodiments are directed to back ear 42design and construction, these embodiments are equally applicable tofront ear 40 design and construction. It should be recognized that anycombination of the following embodiments may be used for the back ear 42and/or the front ear 40.

In alternative embodiments, the diaper 20 may be preformed by themanufacturer to create a pant. A pant may be preformed by any suitabletechnique including, but not limited to, joining together portions ofthe article using refastenable and/or non-refastenable bonds (e.g.,seam, weld, adhesive, cohesive bond, fastener, etc.). For example, thediaper 20 of FIG. 1 may be manufactured with the fastening system 50engaged (i.e., the engaging member 52 is joined to the receiving member54). As an additional example, the diaper 20 of FIG. 1 may bemanufactured with the front ears 40 joined to the back ears 42 by way ofa bond such as an adhesive bond, a mechanical bond, or some otherbonding technique known in the art. Suitable pants are disclosed in U.S.Pat. Nos. 5,246,433; 5,569,234; 6,120,487; 6,120,489; 4,940,464;5,092,861; 5,897,545; and 5,957,908.

As noted above, a construction adhesive is typically used to joincomponents of an absorbent article as the absorbent article is beingassembled. Nonlimiting examples of such joinder using the constructionadhesive include but are not limited to:

-   -   core cover to dusting layer sealing;    -   backsheet 26 to core 28;    -   elastic member 64 to nonwoven and/or film to form a barrier cuff        60 or a gasketing cuff 70.    -   nonwoven to vapor permeable film to form a backsheet 26;    -   barrier cuffs to topsheet 24;    -   receiving member 54 to topsheet 24;    -   ear 40, 42 to backsheet 26.    -   core substrate layer to core absorbent polymer material

As will be recognized, many of these uses involve joinder of a nonwovenmaterial to another material. In some instances nonwoven material isjoined to another nonwoven. In other instances, a nonwoven may be joinedto a film.

Nonwovens in the present invention may be such as those disclosed inU.S. Patent Application Nos. 61/837,286, 8,388,594, 8,226,625,8,231,595, and 8,226,626.

Adhesive

The adhesive material comprises a first polymer comprising a polyolefincomprising a substantially amorphous or randomly polymerized polymermaterial and a second polymer comprising a heterophase polymer.

The first amorphous polymer comprises typically butene (e.g.) 1-buteneand can contain ethylene, propene or a second C₄₋₄₀ olefin polymer.These substantially amorphous low crystallinity polymers have less than10% and preferably less than 5% crystalline character.

The second heterophase olefin polymer comprises a first poly alphaolefin polymer comprising a substantial proportion (greater than 40 or50 mole %) of a propene monomer and comprises an amorphous polymer withsome crystalline content.

The amorphous polymer is a butene-based copolymer (the minimum amount isat least about 30 or 40 or 50 wt. % of 1-butene), which may also bereferred to as a random butene-α-olefin copolymer. The butene copolymerincludes one or more units, i.e., mer units, derived from propene, oneor more comonomer units derived from ethylene or α-olefins includingfrom 4 to about 20 carbon atoms.

The first copolymer comprises about 30 mole %-about 70 mole %,preferably about 40 mole % to about 60 mole % of units derived frombutene. In addition to butene-derived units, the present copolymercontains from about 70 mole %-about 30 mole % to about 60 mole %-about40 mole %, of units derived from preferably ethylene, propene or atleast one C_(5 to 10) alpha-olefin monomer.

In one or more embodiments, the α-olefin comonomer units can also bederived from other monomers such as ethylene, 1-butene, 1-hexane,4-methyl-1-pentene and/or 1-octene. Exemplary alpha-olefins are selectedfrom the group consisting of ethylene, butene-1,pentene-1,2-methylpentene-1,3methylbutene-1,hexene-1,3-methylpentene-1,4-methylpentene-1,3,3-dimethylbutene-1,heptene-1, hexene-1, methylhexene-1, dimethylpentene-1,trimethylbutene-1, ethylpentene-1, octene-1, methylpentene-1,dimethylhexene-1, trimethylpentene-1, ethylhexene-1,methylethylpentene-1, diethylbutene-1, prooylpentane-1, decene-1,methylnonene-1, nonene-1, dimethyloctene-1, trimethylheptene-1,ethyloctene-1, methylethylbutene-1, diethylhexene-1, dodecene-1, andhexadodecene-1.

In one or more embodiments, amorphous copolymer comprises about 30 mole%-about 70 mole %, preferably about 40 mole % to about 60 mole % ofunits derived from butene and from about 70 mole %-about 30 mole % toabout 60 mole %-about 40 mole %, of units derived from at least onealpha-olefin monomer selected from ethylene, propene, 1-hexene or1-octene. Small amounts of α-olefin monomer(s) can be used in the rangeof about 0.1 to 20 mole %. The amorphous polymer has a weight averagemolecular weight (Mw) of about 1,000 to about 25,000 or less, preferablyabout 2,000 to 20,000.

In one or more embodiments, first copolymer comprises about 30 mole%-about 70 mole %, preferably about 40 mole % to about 60 mole % ofunits derived from butene and from about 70 mole %-about 30 mole % toabout 60 mole %-about 40 mole %, of units derived from propene, whilesmall amounts of α-olefin monomer(s) can be used in the range of about0.1 to 20 mole %.

The amorphous polymer has a weight average molecular weight (Mw) ofabout 1,000 to about 50,000 or less, preferably about 5,000 to 45,000.

The amorphous copolymer has a viscosity of less than 10,000 mPa·s (1centipoise [cps]=1 mPa·s), for example about 2000 to 8000 mPa·s, whenmeasured by ASTM D3236 at 190° C. Melt Viscosity was determinedaccording to ASTM D-3236, which is also referred to herein as“viscosity” and/or “Brookfield viscosity”.

Some examples of amorphous polyolefin include the Rextac polymers madeby Huntsman including Rextac E-63, E-65, 2815, 2830, etc. See, forexample Sustic, U.S. Pat. No. 5,723,546 for a description of thepolymers and which is expressly incorporated herein. Other usefulamorphous polymers are sold as Vistoplast® and Eastoflex® materials.

The adhesive material comprises a second polyolefin comprising asubstantially heterophase copolymer. The heterophase polyolefin maycomprise a propene copolymer (i.e.) propene-based polymer with othercomonomer(s). The propene-based polymer backbone preferably comprisespropene and one or more C₂ or C₄₋₂₀ α-olefins. The propene-basedheterophase polymer, for example, may comprise propene and ethylene,hexene or optionally other C₂ or C₄₋₂₀ α-olefins. The polymer comprisesabout 99.5 to about 70 wt. %, preferably about 95 to about 75 wt. % ofunits derived from propene. In addition to propene derived units, thepresent copolymer contains from about 0.1 to 30 wt. % preferably fromabout 5 to 25 wt. %, of units derived from preferably at least C₂₋₄ or aC₅₋₁₀ alpha-olefin.

In one or more embodiments, the second copolymer comprises a majorproportion of propene and about 0.1 to 30 wt. %, or 2 to 25 wt. %ethylene. In one or more embodiments, the second copolymer comprises amajor proportion of propene and about 0.1 to 30 wt. %, or 2 to 25 wt. %1-butene.

In one or more embodiments, the second copolymer comprises a majorproportion of propene and about 0.1 to 30 wt. %, or 2 to 25 wt. %1-hexene. In one or more embodiments, the second copolymer comprises amajor proportion of propene and about 0.1 to 30 wt. %, or 2 to 25 wt. %1-octene.

Other comonomer for use in either the first or second polyolefincomprise ethylene or α-olefins containing 4 to 12 carbon atoms.Exemplary α-olefins may be selected from the group consisting ofethylene; 1-butene; 1-pentene; 2-methyl-1-pentene; 3-methyl-1-butene;1-hexene-3-methyl-1-pentene-4-methyl-1-pentene-3,3-dimethyl-1-butene;1-heptene; 1-hexene; 1-methyl-1-hexene; dimethyl-1-pentene;trimethyl-1-butene; ethyl-1-pentene; 1-octene; methyl-1-pentene;dimethyl-1-hexene; trimethyl-1-pentene; ethyl-1-hexene;1-methylethyl-1-pentene; 1-diethyl-1-butene; propyl-1-pentene; 1-decene;methyl-1-nonene; 1-nonene; dimethyl-1-octene; trimethyl-1-heptene;ethyl-1-octene; methylethyl-1-butene; diethyl-1-hexene; 1-dodecene and1-hexadodecene. Preferred C₄₋₁₀ alpha-olefins are those having 6 to 8carbon atoms, with the most preferred alpha-olefin being 1-hexene and1-octene.

Preferred propene copolymers are copolymers wherein the comonomer isethylene, 1-butene, 1-hexene or 1-octene. The stereo-regular (isotacticor syndiotactic) sequence or block content of the polymers imparts aheterophase (partial amorphous and partial crystalline) character ofcrystallizable content to the polymers. As used herein and as applied tosemi-crystalline heterophase copolymers, the term “crystallizable”describes those polymer sequences or blocks that can crystallize uponcooling. Crystalline content of the solidified semicrystallinecopolymers increases the cohesive strength of the hot melt adhesives.Hot melt adhesive formulations based on metallocene polymerizedsemicrystalline copolymers can eventually build sufficient crystallinecontent over time to achieve good cohesive strength in the formulation.

The second heterophase polymer comprises crystallizable polymer blocksor sequences, preferably of stereoregular sequences of polymerizedmonomer such as ethylene or propene, which sequences are long enough tocrystallize, typically at least repeating or block monomer units persequence.

In preferred embodiments, the crystallizable segments can bestereoregular or isotactic. Isotacticity of the olefin sequences can beachieved by polymerization with the choice of a desirable catalystcomposition. The isotacticity is conventionally measured using DSC orC-13 NMR instrumental techniques.

The heterophase polymer has a crystallinity of at least 5 wt. %, 10 wt.%, 20 wt. %, 40 wt. % or 50 wt. %, preferably between 20% and 80%, morepreferably between 25% and 70%.

The heat of fusion of the heterophase copolymers (by ASTM E793) is about10 J/g to about 70 J/g and about 15 J/g to about 70 J/g, with a meltingpoint less than 150° C. and about 105° C. to about 135° C.

The heterophase polymer has a weight average molecular weight (Mw) ofabout 20,000 or less, preferably about 10,000 or less, preferably about500 to 8,000.

The heterophase copolymer has a viscosity of less than 20,000 mPa·s (1centipoise [cps]=1 mPa·s), for example less than 15000 mPa·s, in certainapplication less than 10,000 mPa·s and less than 5,000 mPa·s whenmeasured at 190° C. using a Brookfield viscometer (as measured by ASTM D3236) which is also referred to herein as “viscosity” and/or “Brookfieldviscosity.”

Some examples of heterophase polymers useful in the hot melt adhesivecompositions of include polyolefin such as polyethylene, polypropylene,and copolymers thereof such as polypropylene based elastomers sold byExxonMobil Chemical of Houston, Tex. under the trade name VISTAMAXX™ andpolyethylene based elastomers such as those sold by Dow Chemical Companyof Midland, Mich. under the trade names AFFINITY™ and ENGAGE™.

Other heterophase polymers that are useful in the hot melt adhesivecompositions include the polyolefin elastomers VISTAMAXX™ 8816,VISTAMAXX™ 2230, and ENGAGE™ 8200. AFFINITY™ GA 1900 has a density of0.870 g/cm3 according to ASTM D792, heat of fusion of 46.1 J/g, and aBrookfield viscosity of 8200 cP at 177° C. according to ASTM D 1084.AFFINITY™ GA 1950 has a density of 0.874 g/cm3 according to ASTM D792,heat of fusion of 53.4 J/g, and a Brookfield viscosity of 17,000 cP at177° C. according to ASTM D 1084. ENGAGE™ 8200 has a density of 0.87g/cm3 according to ASTM D792 and a melt index of 5 g/10 min at 190° C.These olefin elastomers are compatible with the propylene copolymersuseful in the hot melt adhesive compositions and improve physicalproperties such as low temperature adhesive performance withoutsacrificing effective set time.

Any conventional polymerization synthesis processes may prepare thepolyolefin copolymers. Preferably, one or more catalysts, which aretypically metallocene catalysts or Zeigler-Natta, catalysts, are usedfor polymerization of an olefin monomer or monomer mixture.Polymerization methods include high pressure, slurry, gas, bulk,suspension, supercritical, or solution phase, or a combination thereof,preferably using a single-site metallocene catalyst system. Thecatalysts can be in the form of a homogeneous solution, supported, or acombination thereof. Polymerization may be carried out by a continuous,a semi-continuous or batch process and may include use of chain transferagents, scavengers, or other such additives as deemed applicable. Bycontinuous is meant a system that operates (or is intended to operate)without interruption or cessation. For example a continuous process toproduce a polymer would be one where the reactants are continuallyintroduced into one or more reactors and polymer product is continuallywithdrawn. In one embodiment, the propene copolymer described herein isproduced in a single or multiple polymerization zones using a singlepolymerization catalyst. The heterophase polymers are typically madeusing multiple metallocene catalyst blends that obtain desiredheterophase structure.

The compositions disclosed herein can also comprise a plasticizer orplasticizing oil or extender oil that may reduce viscosity or improvetack properties in the adhesive. Any plasticizer known to a person ofordinary skill in the art may be used in the adhesion compositiondisclosed herein. Nonlimiting examples of plasticizers include olefinoligomers, low molecular weight polyolefin such as liquid polybutene,low molecular weight non-aromatic polymers (e.g. REGALREZ 101 fromEastman Chemical Company), phthalates, mineral oils such as naphthenic,paraffinic, or hydrogenated (white) oils (e.g. Kaydol oil or ParaLuxoils (Chevron U.S.A. Inc.)), vegetable and animal oil and theirderivatives, petroleum derived oils, and combinations thereof. Lowmolecular weight polyolefin may include those with Mw as low as 100, inparticular, those in the range of from about 100 to 3000, in the rangeof from about 250 to about 2000 and in the range of from about 300 toabout 1000.

In some embodiments, the plasticizers include polypropylene, polybutene,hydrogenated polyisoprene, hydrogenated polybutadiene, polypiperylene,copolymers of piperylene and isoprene, and the like, having averagemolecular weights between about 350 and about 10,000. In otherembodiments, the plasticizers include glyceryl esters of the usual fattyacids and polymerization products thereof. In some embodiments, theplasticizer may be a polymer of isobutylene. A preferred plasticizercomprises a polyisobutylene polymer. The polymer can comprise majorproportion of isobutylene units or can be represented as:

[—C(CH₃)₂—CH₂-]_(n);

wherein n=15 to 75. Polyisobutylene materials are viscous liquids withmolecular weight of about 200-20,000, about 200-5,000 or about500-2,000. The preferred materials have a Saybolt Universal seconds(SUS) viscosity at 100° C. of about 100 to 20,000. The characteristicfeatures of polyisobutylene are low gas permeability and high resistanceto the action of acids, alkalis, and solutions of salts, as well as highdielectric indexes. They degrade gradually under the action of sunlightand ultraviolet rays (the addition of carbon black slows this process).In industry, polyisobutylene is produced by ionic (AlCl₃ catalyzed)polymerization of the monomer at temperatures from −80° to −100° C.;they are processed using the ordinary equipment of the rubber industry.Polyisobutylene combines easily with natural or synthetic rubbers,polyethylene, polyvinyl chloride, and phenol-formaldehyde resins.

Embodiments of preferred compositions are made with substantially lessthan 40 wt. %, less than 20 wt. % or are substantially free of aneffective amount of a conventional tackifier material that can add anyaspect of open time, substrate wetting or tack to the adhesive material.Avoiding the use of a tackifier reduces adhesive density, adhesive andproduct costs and frees formulators from the use of materials in shortsupply. Further, tackifier can impart undesirable odor in disposablearticles and can also act as carriers of low molecular weightplasticizers (like

process oils that are used in SBC based adhesives) that can weaken thepolyethylene backsheet materials used in articles. Backsheet integrityis becoming more important due to the downsizing of the polyethylenefilm thickness used in these articles. The term “conventional tackifierresins”, means those resins commonly available in the adhesive art andindustry that are used in typical hot melt adhesives. Examples ofconventional tackifing resins included in this range include analiphatic hydrocarbon resins, aromatic modified aliphatic hydrocarbonresins, hydrogenated polycyclopentadiene resins, poly-cyclopentadieneresins, gum rosins, gum rosin esters, wood rosins, wood rosin esters,tall oil rosins, tall oil rosin esters, poly-terpene, aromatic modifiedpoly-terpene, terpene-phenolic, aromatic modified hydrogenatedpoly-cyclopentadiene resins, hydrogenated aliphatic resins, hydrogenatedaliphatic aromatic resins, hydrogenated terpene and modified terpene andhydrogenated rosin esters. Often in conventional formulations suchresins are used in amounts that range from about 40 to about 65 wt. %.

In further embodiments, the compositions disclosed herein optionally cancomprise an antioxidant or a stabilizer. Any antioxidant known to aperson of ordinary skill in the art may be used in the adhesioncomposition disclosed herein. Non-limiting examples of suitableantioxidants include amine-based antioxidants such as alkyl diphenylamines, phenyl-naphthylamine, alkyl or aralkyl substitutedphenylnaphthylamine, alkylated p-phenylene diamines,tetramethyl-diaminodiphenylamine and the like; and hindered phenolcompounds such as 2,6-di-t-butyl-4-methylphenol;1,3,5-trimethyl-2,4,6-tris (3′,5′-di-t-butyl-4′-hydroxybenzyl)benzene;tetra kis [(methylene(3,5-di-t-butyl-4-hydroxyhydrocinnamate)]methane(e.g., IRGANOX™1010, from Ciba Geigy, New York);octadecyl-3,5-di-t-butyl-4-hydroxycinnamate (e.g., IRGANOX™ 1076,commercially available from Ciba Geigy) and combinations thereof. Whereused, the amount of the antioxidant in the composition can be from aboutgreater than 0 to about 1 wt. %, from about 0.05 to about 0.75 wt. %, orfrom about 0.1 to about 0.5 wt. % of the total weight of thecomposition.

In further embodiments, the compositions disclosed herein optionally cancomprise an UV stabilizer that may prevent or reduce the degradation ofthe composition by radiation. Any UV stabilizer known to a person ofordinary skill in the art may be used in the adhesion compositiondisclosed herein. Non-limiting examples of suitable UV stabilizersinclude benzophenones, benzotriazoles, aryl esters, oxanilides, acrylicesters, formamidine carbon black, hindered amines, nickel quenchers,hindered amines, phenolic antioxidants, metallic salts, zinc compoundsand combinations thereof. Where used, the amount of the UV stabilizer inthe composition can be from about greater than 0 to about 1 wt. %, fromabout 0.05 to about 0.75 wt. %, or from about 0.1 to about 0.5 wt. % ofthe total weight of the composition.

In further embodiments, the compositions disclosed herein optionally cancomprise a brightener, colorant or pigment. Any colorant or pigmentknown to a person of ordinary skill in the art may be used in theadhesion composition disclosed herein. Non-limiting examples of suitablebrighteners, colorants or pigments include fluorescent materials andpigments such as triazine-stilbene, coumarin, imidazole, diazole,titanium dioxide and carbon black, phthalocyanine pigments, and otherorganic pigments such as IRGAZINB, CROMOPHTALB, MONASTRALB, CINQUASIAB,IRGALITEB, ORASOLB, all of which are available from Ciba SpecialtyChemicals, Tarrytown, N.Y. Where used, the amount of the brightener,colorant or pigment in the composition can be from about greater than 0to about 10 wt %, from about 0.01 to about 5 wt %, or from about 0.1 toabout 2 wt % of the total weight of the composition.

The compositions disclosed herein may also optionally comprise afragrance such as a perfume or other odorant. Such fragrances may beretained by a liner or contained in release agents such as microcapsulesthat may, for example, release fragrance upon removal of a release linerfrom or compression on the composition.

In further embodiments, the compositions disclosed herein optionally cancomprise filler. Any filler known to a person of ordinary skill in theart may be used in the adhesion composition disclosed herein.Non-limiting examples of suitable fillers include sand, talc, dolomite,calcium carbonate, clay, silica, mica, wollastonite, feldspar, aluminumsilicate, alumina, hydrated alumina, glass bead, glass microsphere,ceramic microsphere, thermoplastic microsphere, barite, wood flour, andcombinations thereof. Where used, the amount of the filler in thecomposition can be from about greater than 0 to about 60 wt. %, fromabout 1 to about 50 wt. %, or from about 5 to about 40 wt. %.

TABLE 1 Substantially Tackifier-Free Adhesive Compositions ComponentEmbodiment Wt. % Wt. % Wt % Amorphous polymer REXTAC E65 90-10 20-8070-40 Heterophase polymer Vistamaxx 10-90 80-20 40-70 PlasticizerPolyisobutylene  0-40  5-35  5-30 Additive Antioxidant/Stabilizer  0-20 1-20  1-15

One substantial advantage in the claimed adhesives relates to a densityof the adhesive formulations. Conventional tackifier is at a densitythat often ranges from about 1.07-1.09 g-cm⁻³. Conventional formulatedadhesives containing a conventional tackifier in amounts of about 40 to60 wt. %, have a density greater than 0.9 g-cm⁻³ or more. The formulatedadhesives of the invention, substantially free of tackifier, havedensities less than 0.9 g-cm⁻³, often in the range about 0.85-0.89g-cm⁻³, often 0.86-0.87 g-cm⁻³. Not only are these adhesives free of theproblems arising from tackifier materials, but the use of the claimedadhesives, and a lower density, permits the use of a reduced amount whenmeasured by weight, resulting in cost savings.

Another aspect are methods of manufacture employing the hot meltadhesive compositions. The method involves application of the moltencompositions to a substrate, followed by contact of the adhesivecomposition with a second substrate within 0.1 second to 5 seconds afterapplication of the adhesive composition to the first substrate, whereinthe contacting results in an adhesive bond between the substrates.

The hot melt adhesive compositions have melt rheology and thermalstability suitable for use with conventional hot melt adhesiveapplication equipment. The blended components of the hot melt adhesivecompositions have low melt viscosity at the application temperature,thereby facilitating flow of the compositions through a coatingapparatus, e.g., coating die or nozzle, without resorting to theinclusion of solvents or extender oil into the composition. Meltviscosities of the hot melt adhesive compositions are between 1500 cPand 3500 cP or about 2000 cP to 3000 cP in mille Pascal-seconds orcentipoise (cP) using a Brookfield thermosel RVT viscometer using arotor number 27 at 176.66° C. (50 rpm, 350° F.). The hot melt adhesivecompositions have a softening point (ASTM D 3461-97 Standard Test Methodfor Mettler Softening Point Method) of about 80° C. to 140° C., in someembodiments about 115° C. to 130° C.

For certain applications, the hot melt adhesive compositions haveeffective set times of about 5 seconds or less, for example about 0.1second to 5 seconds, in some embodiments about 0.1 second to 3 seconds,and in some embodiments about 0.2 second to 1 second. The effective settime of the hot melt adhesives are unexpectedly short, particularlygiven that the open time remains in the acceptable range.

The construction adhesive can be applied using a wide variety of knownapplication methods including but not limited to slot extrusion, sprays,including spiral sprays, and beads. Specific examples include but arenot limited to:

-   -   application of the construction adhesive in a spiral spray or        slot coating to join a topsheet to an underlying nonwoven layer;    -   application of the construction adhesive via slot coating to        join an acquisition layer or a distribution layer to a core        cover;    -   application of beads of the construction adhesive located        between the nonwoven material comprising the cuff and the        backsheet;    -   application of the construction adhesive in a spiral spray or        slot coating to join the topsheet to the backsheet so as to seal        the longitudinal edges of the absorbent article;    -   application of the construction adhesive using slot coating to        join a landing zone (i. e. a receiving member) to the backsheet;    -   application of the construction adhesive using slot coating to        join the core cover to the dusting layer;    -   application of the construction adhesive in a spiral spray to        join the core to the backsheet.    -   application of the construction adhesive in a spiral spray to        join the nonwoven material comprising the cuff to the nonwoven        material comprising the backsheet.

The adhesive is typically applied in an amount of about 1 to about 100or about 4 to about 90 or about 7 to about 70 grams per square meter(g/m²) of resulting bonded material. The material may be applied in anamount of about 0.1 to about 20 or about 0.2 to about 10 or about 0.3 toabout 15 grams per square meter (g/m²) of resulting bonded material. Theadhesive material can be used at an add-on rate of 0.5 to 2 g/m², 0.6 to1.7 g/m² or 0.7 to 1.5 g/m², for absorbent articles.

EXAMPLES

A number of hot melt adhesive compositions were prepared by blendingfirst amorphous copolymer, second heterophase copolymer, polymerplasticizer/diluent and antioxidant under mixing conditions at elevatedtemperatures to form a fully homogenized fluid melt. Mixing temperaturesvaried from about 135 to about 200° C., preferably about 150 to about175° C. A WiseStir® mixer was used to ensure full homogenization ofcomponents into a final adhesive composition.

Examples 1-4

Hot melt adhesive compositions were formulated by melt blending asdescribed below, wherein specific components and amounts of thecomponents are shown in the following table 2.

TABLE 2 Exemplary Adhesive Formulations Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5Ex. 6 Ex. 7 Ex. 8 Source Component wt. % wt. % wt. % wt. % wt. % wt. %wt. % wt. % ExxonMobil Vistamaxx 20 35 35 35 15 15 15 10 Chemical, 8816Houston, TX Huntsman Rextac E-65 59.5 60 55 50 64.5 59.5 59.5 59.5Chemicals Ineos Indapol H-300 20 4.5 9.5 14.5 20 24.99 0 0 Chemicals(Polyiso- butylene) Ineos Indapol H- 0 0 0 0 0 0.5 0.5 0.5 Chemicals1900 (Polyiso- butylene) Ciba Geigy Irganox 1010 0.5 0.5 0.5 0.5 0.5 0.50.5 0.5 Ltd., Basel, (Hindered Switzerland Phenol) Mayzo, Inc. BenetexOB 0 0 0 0 0 0.01 0.01 0.01 Fluorescent Optical Brightener

TABLE 3 Exemplary Adhesive Viscosity Data Brookfield Viscosity @ Ex. 1Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7 Ex. 8 121.1° C. (250° F.) 2620029750 16600 39000   135° C. (275° F.) 7710 12125 9725 7500 8425 71009100 8750 148.9° C. (300° F.) 4675 6350 5325 4525 5150 4200 5325 5375162.8° C. (325° F.) 3075 4190 3500 2980 3475 2800 3550 3375 176.7° C.(350° F.) 2220 2945 2450 2080 2315 1920 2385 2275 Mettler Softening 121125 125 124 120 118 118 115 Point (° C.) Density g/cm³ 0.86-0.870.86-0.87 0.86-0.87 0.86-0.87 0.86-0.87 0.86-0.87 0.86-0.87 0.86-0.87ASTM 792

These data indicates that the materials will provide excellentconstruction bonding in disposable absorbent articles. Note viscosityrelates to the resistance to flow of the material under certainconditions. This distinctive property determines the flowability, degreeof wetting, and penetration of the substrate by the molten polymer. Itprovides an indication of its processability and utility as a hot meltadhesive material. Melt viscosity is generally directly related to apolymer molecular weight and is reported in Millipascal-second's orcentipoise (cP) using a Brookfield thermosel RVT viscometer using arotor number 27 at the stated temperature.

Mettler softening point in degrees Centigrade or degrees Fahrenheit istypically measured using ASTM D3104. The amorphous nature of thepolyolefin materials results in a melting point that is not sharp ordefinite. Rather as the temperature increases, amorphous polymersgradually change from a solid to a soft and then to a liquid material.No clearly defined glass transition or melting temperature is oftennoted. This temperature testament that generally measures the precisetemperature at which a disc of polymer sample, heated at a rate of 2° C.per minute or 10° F. per minute becomes soft enough to allow the testobject, a steel ball (grams) drops through the sample. The softeningpoint of a polymer reported in degrees Centigrade or degrees Fahrenheitis important because it typically indicates the polymer's heatresistance, useful application temperatures and solidification points.

The claims may suitably comprise, consist of, or consist essentially of,or be substantially free of any of the disclosed or recited elements.The invention illustratively disclosed herein can also be suitablypracticed in the absence of any element which is not specificallydisclosed herein.

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numeral values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm”.

All documents cited in the Detailed Description of the Invention are, inrelevant part, incorporated herein by reference; the citation of anydocument is not to be construed as an admission that it is prior artwith respect to the present invention. To the extent that any meaning ordefinition of a term in this written document conflicts with any meaningor definition of the term in a document incorporated by reference, themeaning or definition assigned to the term in this written documentshall govern.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

What is claimed is:
 1. A disposable absorbent article having alongitudinal centerline and a lateral centerline, a front waist regionwith a front waist edge, a rear waist region with a rear waist edge, acrotch region disposed between the front and rear waist regions and twospaced apart longitudinal side edges joining the front waist edge to therear waist edge and comprising an assembly of components, wherein theassembly of components comprises: a) a topsheet; b) a backsheetunderlying the topsheet; c) an absorbent core disposed between thetopsheet and the backsheet, wherein the absorbent core comprises atleast one of a core cover, a dusting layer, an acquisition layer, adistribution layer, and a storage member; d) at least one additionalcomponent selected from the group consisting of: (i) a fastening systemfor joining the front waist region to the rear waist region when thedisposable absorbent article is worn; (ii) barrier cuffs lying adjacentand inboard one of the longitudinal side edges; (iii) gasketing cuffslying between the longitudinal side edge and the barrier cuff; (iv)front ears disposed in the front waist region; (v) back ears disposed inthe rear waist region; and (vi) a receiving member; and e) a hot meltadhesive composition joining at least two of the assembly of componentstogether, wherein the hot melt adhesive composition comprises: (i) atleast 10 wt. % of an amorphous polyolefin copolymer comprising (a) fromabout 30 mole % to about 70 mole % of 1-butene monomer units; and (b) asecond C₄₋₄₀ olefin polymer; (ii) from about 10 wt. % to about 90 wt. %of a heterophase polyolefin propylene copolymer composition comprisingpropene comonomer units and a comonomer unit selected from the groupconsisting of ethylene, 1-hexene, 1-octene, and amorphous blocks andcrystalline blocks; and (iii) from about 0.05 wt. % to about 0.75 wt. %of an antioxidant; wherein the hot melt adhesive composition issubstantially free of tackifies; and wherein the hot melt adhesivecomposition has a softening point from about 80° C. to 140° C. whenmeasured using ASTM D 3461-97.
 2. The disposable absorbent article ofclaim 1, wherein the amorphous polyolefin copolymer comprises from about40 mole % to about 70 mole % of 1-butene monomer units.
 3. Thedisposable absorbent article of claim 1, wherein the amorphouspolyolefin copolymer comprises from about 50 mole % to about 70 mole %of 1-butene monomer units.
 4. The disposable absorbent article of claim1, wherein the amorphous polyolefin copolymer comprises from about 50mole % to about 60 mole % of 1-butene monomer units.
 5. The disposableabsorbent article of claim 1, wherein the hot melt adhesive compositionjoins the acquisition layer to the core cover.
 6. The disposableabsorbent article of claim 1, wherein the hot melt adhesive compositionjoins the distribution layer to the core cover.
 7. The disposableabsorbent article of claim 1, wherein the hot melt adhesive compositionjoins the topsheet to the backsheet adjacent a longitudinal edge of thedisposable absorbent article.
 8. The disposable absorbent article ofclaim 1, wherein the hot melt adhesive composition joins the receivingmember to the backsheet.
 9. The disposable absorbent article of claim 1,wherein the hot melt adhesive composition joins the core cover to thedusting layer.
 10. The disposable absorbent article of claim 1, whereinthe hot melt adhesive composition joins the core cover to the backsheet.11. The disposable absorbent article of claim 1, wherein the hot meltadhesive composition joins the dusting layer to the backsheet.
 12. Adisposable absorbent article having a longitudinal centerline and alateral centerline, a front waist region with a front waist edge, a rearwaist region with a rear waist edge, a crotch region disposed betweenthe front and rear waist regions and two spaced apart longitudinal sideedges joining the front waist edge to the rear waist edge and comprisingan assembly of components, wherein the assembly of components comprises:a) a topsheet; b) a backsheet underlying the topsheet; c) an absorbentcore disposed between the topsheet and the backsheet, wherein theabsorbent core comprises at least one of a core cover, a dusting layer,an acquisition layer, a distribution layer, and a storage member; d) atleast one additional component selected from the group consisting of:(i) a fastening system for joining the front waist region to the rearwaist region when the disposable absorbent article is worn; (ii) barriercuffs lying adjacent and inboard one of the longitudinal side edges;(iii) gasketing cuffs lying between the longitudinal side edge and thebarrier cuff; (iv) front ears disposed in the front waist region; (v)back ears disposed in the rear waist region; and (vi) a receivingmember; and e) a hot melt adhesive composition joining at least two ofthe assembly of components together, wherein the hot melt adhesivecomposition comprises: (i) at least 10 wt. % of an amorphous polyolefincopolymer comprising (a) from about 40 mole % to about 70 mole % of1-butene monomer units; and (b) a second C₄₋₄₀ olefin polymer; (ii) fromabout 10 wt. % to about 90 wt. % of a heterophase polyolefin propylenecopolymer composition comprising propene comonomer units and a comonomerunit selected from the group consisting of ethylene, 1-hexene, 1-octene,and amorphous blocks and crystalline blocks; and (iii) from about 0.05wt. to about 0.75 wt. % of an antioxidant; wherein the amorphouspolyolefin copolymer has a viscosity from about 2000 mPa·s to about 8000mPa·s when measured by ASTM D3236 at 190° C.; and wherein the hot meltadhesive composition is substantially free of tackifier.
 13. Thedisposable absorbent article of claim 12, wherein the hot melt adhesivecomposition has a softening point from about 80° C. to 140° C. whenmeasured using ASTM D 3461-97.
 14. The disposable absorbent article ofclaim 12, wherein the amorphous polyolefin copolymer comprises fromabout 30 mole % to about 70 mole % of propene monomer units.
 15. Thedisposable absorbent article of claim 12, wherein the amorphouspolyolefin copolymer comprises from about 45 mole % to about 65 mole %of 1-butene monomer units.
 16. The disposable absorbent article of claim12, wherein the hot melt adhesive composition joins the acquisitionlayer to the core cover.
 17. The disposable absorbent article of claim12, wherein the hot melt adhesive composition joins the distributionlayer to the core cover.
 18. A disposable absorbent article having alongitudinal centerline and a lateral centerline, a front waist regionwith a front waist edge, a rear waist region with a rear waist edge, acrotch region disposed between the front and rear waist regions and twospaced apart longitudinal side edges joining the front waist edge to therear waist edge and comprising an assembly of components, wherein theassembly of components comprises: a) a topsheet; b) a backsheetunderlying the topsheet; c) an absorbent core disposed between thetopsheet and the backsheet, wherein the absorbent core comprises atleast one of a core cover, a dusting layer, an acquisition layer, adistribution layer, and a storage member; d) at least one additionalcomponent selected from the group consisting of: (i) a fastening systemfor joining the front waist region to the rear waist region when thedisposable absorbent article is worn; (ii) barrier cuffs lying adjacentand inboard one of the longitudinal side edges; (iii) gasketing cuffslying between the longitudinal side edge and the barrier cuff; (iv)front ears disposed in the front waist region; (v) back ears disposed inthe rear waist region; and (vi) a receiving member; and e) a hot meltadhesive composition joining at least two of the assembly of componentstogether, wherein the hot melt adhesive composition comprises: (iv) atleast 10 wt. % of an amorphous polyolefin copolymer comprising (a) fromabout 40 mole % to about 60 mole % of 1-butene monomer units; and (b) asecond C₄₋₄₀ olefin polymer; (i) from about 10 wt. % to about 90 wt. %of a heterophase polyolefin propylene copolymer composition comprisingpropene comonomer units and a comonomer unit selected from the groupconsisting of ethylene, 1-hexene, 1-octene, and amorphous blocks andcrystalline blocks; and (ii) from about 0.05 wt. % to about 0.75 wt. %of an antioxidant; wherein the amorphous polyolefin copolymer has aviscosity from about 2000 mPa·s to about 8000 mPa·s when measured byASTM D3236 at 190° C.; wherein the hot melt adhesive composition is freeof tackifier; and wherein the hot melt adhesive composition has asoftening point from about 80° C. to 140° C. when measured using ASTM D3461-97.
 19. The disposable absorbent article of claim 18, wherein thehot melt adhesive composition joins the topsheet to the backsheetadjacent a longitudinal edge of the disposable absorbent article. 20.The disposable absorbent article of claim 18, wherein the disposableabsorbent article comprises barrier cuffs lying adjacent and inboard oneof the longitudinal side edges.